RD Controls Hardware Release Note 28.2 <P> Preliminary Design <P> C1080 Multibus Interface Module <P> CAMAC Function Codes

RD Controls Hardware Release Note 28.2

Preliminary Design

C1080 Multibus Interface Module

CAMAC Function Codes


September 1, 1992


The beamline control system interfaces with modules residing in multibus crates used to obtain information from and to control devices in the various beamline cryogenic systems. A cryogenics multibus crate may contain a maximum of two A/D-D/A modules, two actuator controller modules, two digital status and control modules, and one temperature resistor module.

An A/D-D/A module contains 32 A/D data channels and 2 D/A channels. For interfacing purposes, the A/D section and the D/A section are each identified as a separate device having multiple data channels. Because there may be two A/D-D/A modules in a multibus crate, the A/D device is considered to have a maximum of 64 (2 * 32) data channels and the D/A device is considered to have a maximum of 4 (2 * 2) data channels. The other multibus module which is treated as a collection of distinct devices is the digital status and control module. Using this scheme of devices and channels, Table 1 lists the maximum configuration a multibus currently may contain.

CAMAC Function Codes

Because a multibus device (e.g., digital status) may have as many as 80 channels, it is not possible to use only one CAMAC operation to read information from a specific device and channel. It is necessary to first perform a write operation (F17A0) to specify the initial channel number. After that, each read operation directed to a particular device returns the requested information and then increments the channel number. Note that only one channel number variable is maintained. Each time data is to be obtained from a different device, the initial channel number must be specified again. A minimum of 7 bits is required to specify the largest channel number currently being used. A field width of 8 bits is actually used, so the maximum channel number which may potentially be used is 255.

Read a 16-bit data word and then increment the channel number. A valid reading is returned only for the A/D device and the temperature device. A request for any other device or for a channel number greater than the maximum for the requested device results in a no Q. The average value is calculated using the previous eight data readings.

Read the current value of the channel number, which is the number of the channel to be used for the next read or write operation directed to the channel of a device. Note that this channel value will not be the same as the value initially specified if read or write operations have been issued to the device and have caused the channel number to be incremented.
Read the selected table ID number and the entry offset. Parameter tables may be associated with particular device and channel combinations. This operation selects the initial entry of a particular table to be referenced by a table read or write operation. As with the channel number variable, there is only one table/offset variable pair. Hence, the table ID and initial entry offset need to be specified prior to referencing parameter table data for a different device.

bits 15 - 8: table ID

bits 7 - 0: entry offset

Read a 16-bit data word from the selected parameter table of the selected device and channel and then increment the entry offset to the next word. Note that the channel number is not incremented by this operation nor by the the F1A1.

Read engine requested position.

Re0d engine tolerance.

Read actuator requested position.

Read actuator tolerance.

Read status register and then increment the channel number

Read LAM mask

Read LAM request register

Read module number

Read version number

Read FOP status

Read FOP data

Read the hardware serial number of the module

Test LAM

Module reset

Clear LAM

Write the channel number
Write the table ID number and the entry offset

bits 15 - 8: table ID

bits 7 - 0: entry offset

Write a 16-bit data word to the current entry in the selected table and then increment the entry offset to the next word

Write engine requested position.

Write engine tolerance.

Write actuator requested position.

Write actuator tolerance.

Write LAM mask

Write LAM request register

Write FOP command

Write FOP data to buffer

Set to 0 (OFF or OPEN) or 1 (ON or CLOSED) and then increment the channel number

Disable LAM

Enable LAM

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